Yo-yo having modifiable side members

ABSTRACT

The invention is an improved yo-yo that features unique multi-piece sides that have removable shape disks secured by a novel fastening system. The fastening system enables lockable securement of the shape disks via a sliding ratchet-type detent apparatus that can be operated without tools. By replacing one set of shape disks with another, a user can change the shape of the yo-yo and/or change the material of the rim of each of the yo-yo&#39;s sides. This enables a user to adapt the yo-yo&#39;s performance characteristics to suit the user&#39;s needs.

FIELD OF THE INVENTION

The invention is in the field of user-manipulated toys. More particularly, the invention is an apparatus in the form of a yo-yo adapted to enable a user to quickly and easily change the yo-yo's shape and/or rim material. This is accomplished through the use of interchangeable shape disks and a fastening system that releasably secures the shape disks and is easily operated without the need for tools.

BACKGROUND OF THE INVENTION

Most yo-yos are in the form of two disk-shaped side members that are connected to each other by some form of axle structure. The side members are usually of unitary construction and are made out of plastic, metal or wood. The axle structure is secured to the center of both side members and may be an assembly of multiple parts, or merely be in the form of a dowel or a riveted pin. In many modern yo-yos, the axle structure includes a center-located bearing or other member that is secured to, and rotatable on, an elongated axle pin.

The axle structure also forms an anchor for one end of a string-type tether. This is accomplished by having the tether's end-located loop encircle a portion of the axle structure. The free end of the tether is usually tied to create a loop that can be placed about one of a user's fingers to thereby secure the yo-yo to the user's hand.

When the tether is wound about the axle structure and the yo-yo is released from the user's hand, the yo-yo will begin to rapidly spin as it moves away from the user's hand and the tether unwinds from the axle structure. Once the tether is fully unwound, the yo-yo may “sleep” at the end of the tether, whereby the yo-yo continues to spin without the tether rewinding on the axle structure. A user can then perform a quick hand movement to cause the yo-yo to return to his or her hand.

Over the years, many different shapes have been employed for the yo-yo's side members. Traditional yo-yos will usually feature substantially planar side members that have a bulge in the area of the rim to provide an improved weight distribution that increases spin time and stability.

A design for the yo-yo's side members that has become very popular in recent years provides the yo-yo with what is commonly referred to as a “butterfly” shape. In a butterfly yo-yo, each side member's central portion is stretched outwardly, away from the center of the yo-yo, thereby increasing the width of the yo-yo and giving the yo-yo a butterfly shape when viewed in cross-section.

Besides changes in the yo-yo's shape, there have also been a number of different materials used for, or on, the rim portion of each of the yo-yo's side members. For example, it is known to place a relatively soft rubber o-ring on the periphery of each of the yo-yo's side members. Also, there have been yo-yo's developed that employ a relatively soft rubber material for the rim portion of each side member.

The different shapes and materials employed in a yo-yo's side members not only make the yo-yo distinctive, they also affect the yo-yo's performance. For example, a user performing looping tricks with a yo-yo will usually prefer a traditionally shaped yo-yo that has substantially planar side members. Such a shape is best at looping since the weight distribution is close to the tether's attachment point on the yo-yo, thereby enabling the yo-yo to flip over relatively easily during each loop. For yo-yo tricks in which the user attempts to catch the spinning yo-yo on a medial portion of the tether, a butterfly shaped yo-yo is preferred. The more widely spaced-apart rims of the side members improve the yo-yo's stability whereby the yo-yo is less prone to tilt off the tether. Furthermore, the wider stance of a butterfly-shaped yo-yo facilitates a user being able to land the yo-yo on a medial portion of the tether.

Yo-yos with soft rims also have their place. While a soft rim is not suitable for some tricks, such as “walk the dog” where a spinning rim will contact a hard and possibly abrasive surface, a rubber rim is preferable for off-string tricks. For off-string tricks, the user disconnects the yo-yo from the tether and uses the yo-yo much in the same way as one would use a diablo-type toy. During the performance of off-string tricks, it is not uncommon for the yo-yo to inadvertently contact a hard object or surface, a happenstance ameliorated through the use of soft/flexible rims. In addition, soft rims are appreciated by some beginners since they can cushion a hard return that results when a fast spinning yo-yo rapidly returns to the user's hand.

To take advantage of the different characteristics provided by different shapes and materials used for yo-yo side members, many experienced yo-yo players will own a large variety of yo-yos. This enables the player to pick a yo-yo from his or her collection that will work best for the particular trick(s) that the player wishes to perform. However, the costs involved in buying and maintaining a large number of yo-yos can be considerable. In addition, transporting a large number of yo-yos can be bothersome and is usually accomplished using a bulky and expensive transport case that is specially adapted for carrying yo-yos.

In the past, there have been yo-yos that feature side members that may be reversed, disassembled or that have removable flexible rims. However, the prior art does not provide a modifiable yo-yo that is easy to modify and that may assume a large number of different shapes or provide different rim materials.

SUMMARY OF THE INVENTION

The invention is an improved yo-yo that features side members that have removable shape disks secured by a hand-operable fastening system. By replacing one set of shape disks with another, a user can change the shape of the yo-yo and/or change the material of the rim portion of the yo-yo's side members. This enables a user to adapt the yo-yo's performance characteristics to suit the user's needs.

Like most other yo-yos, a yo-yo in accordance with the invention includes a central axle structure to which the tether is attached and that connects together the yo-yo's two side members in a spaced-apart relation. However, unlike most other yo-yos, a yo-yo in accordance with the invention has side members that are an assemblage of parts and can be readily modified.

Each side member includes a hub and a removable shape disk secured to said hub. The peripheral portion of the shape disk functions as the side member's rim and defines the ultimate shape of the side member. The shape disk is fixedly positioned on the hub using a plurality of studs that extend into complementary apertures. In a first embodiment of the invention, the studs extend outwardly from the hubs, extend through shaped apertures in the shape disks, and are received into shaped bores in a lock disk located adjacent the outwardly-facing surface of each of the shape disks. In a second embodiment of the invention, the studs are formed in the shape disks and extend into shaped bores/apertures in the hubs. A hand-operable fastening system is then employed to apply pressure on an outwardly-facing surface of the lock disk (or, in the second embodiment, the shape disk) and thereby secure the shape disk in place.

The fastening system features a multi-detent locking engagement between a fastener member and the lock disk (or, in the second embodiment, the shape disk). In said system, the penultimate and final rotations of the fastener member are preferably accompanied by a clicking sound as the member lockingly engages the lock disk (or, in the second embodiment, the shape disk) multiple times per revolution. The fastener member also includes shaped exterior portions that are easy to grasp and enable the user to rotate the fastener member with little effort and without the need for tools.

The invention allows a user to remove one set of shape disks from the yo-yo and replace them with another set of shape disks that may have a different shape and/or that are entirely or partially made of a different material. For example, the yo-yo can initially be set for looping whereby it features shape disks that give the yo-yo's side members a traditional size and shape. In such a yo-yo, the side members are substantially planar, closely spaced from each other and each has a diameter of about 2.25 inches. The user can then quickly and easily remove the yo-yo's shape disks and attach new shape disks that convert the yo-yo into a butterfly shape that is ideal for string tricks. As another alternative, the user can replace one set of shape disks with another wherein the first shape disks have hard rim portions and each of the replacement shape disks has a rim portion made of a soft resilient material. A user can even replace the shape disks whereby the yo-yo is converted into a diablo-type toy.

The invention is therefore a yo-yo having side members that can be easily modified by a user without the need for special tools. Modification of the side members enables the yo-yo's performance characteristics to be optimized for different types of tricks. By substituting different shape disks, the yo-yo can effectively take the place of multiple yo-yos. This negates the need for the user to own, maintain and transport multiple yo-yos. In addition, a user modifiable yo-yo can provide increased interest to a user through the yo-yo's extended range of usability and the player's ability to decide on the best manner in which to modify the yo-yo for the performance of particular tricks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a first embodiment of a yo-yo in accordance with the invention, with the right-hand portion of the yo-yo shown in cross-section.

FIG. 2 is a front view of the yo-yo shown in FIG. 1, with the right-hand portion shown in exploded fashion.

FIG. 3 is a side view showing the tether-facing surface of one of the hubs of the yo-yo shown in FIG. 1, taken at the plane labeled 3-3 in FIG. 2.

FIG. 4 is a side view showing the outwardly-facing surface of the hub shown in FIG. 3, taken at the plane labeled 4-4 in FIG. 2.

FIG. 5 is a side view showing the inwardly-facing surface of one of the shape disks of the yo-yo shown in FIG. 1, taken at the plane labeled 5-5 in FIG. 2.

FIG. 6 is a side view showing the outwardly-facing surface of the shape disk shown in FIG. 5, taken at the plane labeled 6-6 in FIG. 2.

FIG. 7 is a side view showing the inwardly-facing surface of one of the lock disks of the yo-yo shown in FIG. 1, taken at the plane labeled 7-7 in FIG. 2.

FIG. 8 is a side view showing the outwardly-facing surface of the lock disk shown in FIG. 7, taken at the plane labeled 8-8 in FIG. 2.

FIG. 9 is a side view showing the inwardly-facing surface of one of the fastener members of the yo-yo shown in FIG. 1, taken at the plane labeled 9-9 in FIG. 2.

FIG. 10 is a side view showing the outwardly-facing surface of the fastener member shown in FIG. 9, taken at the plane labeled 10-10 in FIG. 2.

FIG. 11 is a cross-sectional view of a second embodiment of a shape disk in accordance with the invention.

FIG. 12 is a cross-sectional view of a third embodiment of a shape disk in accordance with the invention.

FIG. 13 is a front view of a second embodiment of a yo-yo in accordance with the invention, with the right-hand portion of the yo-yo shown in cross-section.

DETAILED DESCRIPTION OF THE DRAWINGS

Looking now to the drawings in greater detail, wherein like reference numerals refer to like parts throughout the several figures, there is indicated by the numeral 1 a yo-yo in accordance with the invention.

The yo-yo 1 includes first and second side members 2 that are connected together via an axle structure 4. A string-type tether 6 includes a loop portion 8 that encircles a center portion of the axle structure. The tether's distal end (not shown) will normally be tied to create a loop to enable a temporary securement of said end to one of a user's fingers.

The axle structure 4 is preferably an assemblage of parts that includes an axle pin 10 and a ball-bearing unit 12. The axle pin is preferably in the form of a straight rod that has exterior threads 14 at each end.

The ball bearing unit 12 is preferably conventional in design and comprises an inner race 16 that defines a center opening 18, an outer race 20 and a plurality of ball bearings 22 located between the races. It should be noted that other types of rotatable units or members could replace the ball bearing unit. Alternatively, the ball bearing unit can be dispensed with when the yo-yo's tether is attached directly to the axle pin or to a structure fixedly secured to said pin.

Each side member 2 includes a hub 24 (note FIGS. 1-4) that has an inwardly-facing surface 26, an outwardly-facing surface 28 and an outwardly-extending nipple portion 30. A thru-bore 32 extends through the center of the hub. Preferably, each hub is made of a rigid, or substantially rigid, plastic material. Alternatively, the hubs can be made of other materials, including metal, wood, rubber or be a composite or assemblage of rigid and/or non-rigid parts.

The inwardly-facing surface 26 of each hub, which may also be referred to as a tether-facing surface, surrounds a hexagonally-shaped cavity 34 located at its center. Fixedly secured in said cavity is a hex nut 36 that has a threaded thru-bore 38. The nut is preferably sized to create an interference fit with the cavity and it is preferably pressed into the hub. Alternatively, other shapes or types of nuts, or other securement methods, such as the use of adhesives or sonic welding, may be employed.

The hex nuts 36 are preferably made of a metal material, but may also be made of other materials, such as plastic or wood. The hex nuts are sized and/or shaped whereby they can contact the bearing's inner race 14, but cannot contact the bearing's outer race 20. It should be noted that the surface of the outer race is substantially perpendicular to the tether-facing surface 26 of each hub and does not contact either of the hubs. Since the bearing's outer race does not contact the hex nuts or the hubs, it is free to spin and can therefore move independently of the hubs.

To facilitate the return of the yo-yo, the tether-facing surface 26 of each hub preferably includes a slight taper that angles toward the center of the yo-yo and extends from the surface's outer edge to the periphery of the hub's cavity 34. The reduction in string gap caused by the taper allows the tether to bunch up proximate the bearing unit and thereby become snagged on the surfaces 26 when a user causes the tether to go slack when he or she wants the yo-yo to return. Once the tether is snagged, the tether becomes locked to the spinning hubs and, as a result, will wind about the axle structure. The tether winding about the axle structure causes the yo-yo to return to the user's hand.

The two hubs preferably have identical tether-facing surfaces. The tether-facing surface 26 of each hub may also, or instead, include a starburst-shaped array of elongated, radially-extending engagement ribs that protrude toward said tether from the tether-facing surface. Other known types of engagement structures used in yo-yos, such as an array of indentations, spaced pads/protrusions or movable ribs, may also be alternatively employed.

Each hub's nipple portion 30 includes a circular cavity 40 adapted to inwardly contain a bushing 42 made of nylon or some other deformable and/or resilient material. The bushing has a thru-bore 44 located at its center.

As can be seen in FIGS. 1, 2 and 4, the outwardly-facing surface 28 of each hub includes an inner ring of outwardly-extending, cylindrically-shaped studs 46 and an outer ring of outwardly-extending, rectilinearly-shaped studs 48.

Located adjacent the outwardly-facing surface of each hub is a shape disk 50 (note FIGS. 1, 2, 5 and 6). Each shape disk includes an inwardly-facing surface 52, an outwardly-facing surface 54 and a center-located thru-hole 56. The thru-hole has a diameter slightly greater than that of the hub's nipple portion. Located radially outward from the center-located thru-hole are an inner ring of circular apertures 60 and an outer ring of rectangular apertures 62.

Located adjacent the outwardly-facing surface of each shape disk is a lock disk 64 (note FIGS. 1, 2, 7 and 8). Each lock disk includes an inwardly-facing surface 66, an outwardly-facing surface 68 and a center-located thru-hole 70. The thru-hole has a diameter slightly greater than that of the hub's nipple portion. The lock disk also includes an inner ring of circular bores 72 and an outer ring of rectangular bores 74. The bores 72 and 74 are complementary in shape to the hub's studs, 46 and 48 respectively. Located in the outwardly-facing surface of the lock disk is at least one indentation 76. In the embodiment shown, a plurality of indentations 76 are positioned in a circular array.

Located adjacent the outwardly-facing surface of the lock disk is a fastener member 80 (note FIGS. 1, 2, 9 and 10). The fastener member includes an inwardly-facing surface 82, an outwardly-facing surface 84 and a center-located bore 86. The bore is of approximately the same diameter as the hub's nipple portion and has interior threads 88 complementary to threads 90 located on the exterior surface of the hub's nipple portion.

The inwardly-facing surface of the fastener member includes at least one protuberance 92 that extends outwardly from said surface. In the embodiment shown, two protuberances 92 are employed. It should be noted that the indentations 76 of the lock disk are complementary in shape and size to the protuberances 92 and are located at the same radial distance from the yo-yo's axis as said protuberances.

The outwardly-facing surface of the fastener member includes a raised surface having two shaped indentations 94. The indentations enhance a user's ability to grasp the outer surface of the fastener member with his or her fingers and then to subsequently turn the fastener member.

When a yo-yo 1 is assembled, the ball bearing unit 12 is first centered on the axle pin 10 with said pin extending through the bearing's center opening 18. Next, the hubs 24 are threaded onto opposite ends of the axle pin via their hex nuts 36 engaging threads 14. Each hub is rotated relative to the axle pin until its hex nut is proximate the bearing unit and the axle pin extends into its bushing 42. The thru-bore 44 of each side member's bushing 42 is sized whereby the threads of the axle pin will deformably engage the bushing. This engagement acts to increase the torque required to rotate the side member 2 relative to the axle pin, thereby providing a mechanism for adjustable string gap in which one changes the width of the space located between the yo-yo's two side members.

Next, the user would most likely finish assembling one side member at a time. To finish the assembly of a side member, the user would place a shape disk 50 onto the side member's hub, with the hub's nipple portion fitting through the shape disk's center thru-hole 56 and the hub's studs 46 and 48 aligned with, and extending through, the shape disk's apertures 60 and 62, respectively. The studs extending through the shape disk's apertures act to prevent the shape disk from rotating relative to the hub.

It should be noted that while the studs 46 are shown having a different shape than studs 48, the sets of studs may alternatively be similarly shaped. However, the use of studs of different shapes facilitates proper placement of the shape disk onto the hub. The apertures 60 and 62 in each shape disk will have shapes complementary to the studs. Furthermore, while two rings of studs and apertures are shown, a single ring or other shaped array of each may instead be employed. However, multiple rings provide an even distribution of securement forces over the center area of the shape disk. Also, studs fitting through apertures are but one kind of interlocking engagement apparatus that may be employed to engage the shape disk to the hub to prevent relative rotation. Other forms of engagement apparatus, such as clips, VELCRO, interlocking shapes, etc. may be employed to interlock, and thereby engage, the shape disk with the hub.

Once the shape disk is properly positioned, the lock disk 64 is placed against the outwardly-facing surface of the shape disk. This is accomplished by fitting the hub's nipple portion through the center thru-hole 70 of the lock disk as the hub's studs 46 and 48 are received within the complementary bores, 72 and 74 respectively, of the lock disk.

The components of the side member are then secured together using the fastener member 80. The outer end of the hub's nipple portion is inserted into the threaded center bore 86 of the fastener member. The user then rotates the fastener member by hand in a direction whereby the fastener member's threads 88 engage threads 90 of the hub's nipple portion and the fastener member moves toward the lock disk.

As soon as the fastener member is rotated into contact with the lock disk, a clicking noise will be heard. The noise is created as the fastener member's protuberances 92 slidingly engage the lock disk's indentations 76. Each indentation 76 functions as a detent and with each click, the protuberances are at least partially received within the indentations to thereby create a locking engagement. Preferably, multiple detents/indentations 76 are employed to provide multiple points where the fastener member can be lockingly engaged per revolution of the fastener member.

The user will preferably continue turning the fastener member by hand until all of the components of the side member are pressed together by the fastener member and the fastener member is tight against the lock disk. The final click provides a locking engagement that helps to prevent inadvertent loosening/rotating of the fastener member.

To disassemble either of the side members of the yo-yo 1, one merely rotates the side member's fastener member in the opposite direction after overcoming the locking engagement between the fastener member's protuberances and the lock disk's indentations. Once the fastener member is removed from the hub's nipple portion, the lock disk and shape disk can then be removed.

The above procedure allows a user to quickly and easily change the look and/or rim material of the side members of yo-yo 1. For example, the yo-yo 1 is shown with shape disks 50 that provide the yo-yo with the look of a diablo. When the shape disks 50 are made of a resilient material, the yo-yo 1 is thereby optimized for the performance of off-string tricks. If the user instead wishes to perform tricks that involve looping the yo-yo 1, the user would disassemble the yo-yo's side members and replace each of the yo-yo's shape disks 50 with a shape disk 96 per FIG. 11. Once the yo-yo is reassembled with the new shape disks, it would have the optimum shape for looping. Alternatively, the user could disassemble the yo-yo 1 and replace each shape disk 50 with a shape disk 98 per FIG. 12. Once the yo-yo is reassembled, the yo-yo would have a butterfly shape and thereby be optimized for the performance of string tricks.

FIG. 13 shows a second embodiment of a yo-yo 100 in accordance with the invention. Unlike the first embodiment, yo-yo 100 does not have a lock disk and the fastener member 80 of each side member 102 directly abuts the side member's shape disk 104. In this embodiment, each shape disk's inwardly-facing surface 106 features an inner ring of studs 108 and an outer ring of studs 110. The studs 108 and 110 extend toward the yo-yo's center and are received within complementary bores, 112 and 114 respectively in the side member's hub 116. The outwardly-facing surface 118 of the side member's shape disk includes a plurality of indentations 120 that are complementary in size, shape and location to protuberances 92 located on the inwardly-facing surface of the fastener member.

It should be noted that the fastening system, as taught herein, may be employed with other types of yo-yos than the ones shown. Furthermore, while only a few shape disks have been shown and described, the shape disks used in the yo-yos 1 and 90 may have any shape and may be made of any material or assemblage of materials.

The preferred embodiments of the invention disclosed herein have been discussed for the purpose of familiarizing the reader with the novel aspects of the invention. Although preferred embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of the invention as described in the following claims. 

1. A yo-yo comprising: first and second side members secured together in a spaced-apart relation by an axle structure; a tether secured to a portion of said axle structure; first and second hubs, wherein said first hub forms a portion of said first side member and said second hub forms a portion of said second side member, and wherein each of said hubs has a tether-facing surface; first and second shape disks, wherein said first shape disk forms a portion of said first side member and said second shape disk forms a portion of said second side member, wherein said first shape disk is releasably engaged to said first hub by an interlocking engagement whereby said first shape disk cannot rotate relative to said first hub, and wherein said second shape disk is releasably engaged to said second hub whereby said second shape disk cannot rotate relative to said second hub; first and second fastener members, wherein said first fastener member is releasably engaged to said first hub and functions to releasably secure said first shape disk to said first hub, and wherein said second fastener member is releasably engaged to said second hub and functions to releasably secure said second shape disk to said second hub; and wherein each side member's shape disk includes a portion that at least partially forms the exterior surface of the side member's rim, and wherein a user can change the shape of the yo-yo by removing each side member's shape disk and installing in its place a replacement shape disk that has a different shape than the shape disk that was removed.
 2. The yo-yo of claim 1 wherein said first hub includes a plurality of outwardly-extending studs that are aligned with, and extend through, a plurality of apertures located in the first shape disk to thereby releasably engage the first shape disk to the first hub.
 3. The yo-yo of claim 2 wherein said apertures have a size and shape complementary to said studs.
 4. The yo-yo of claim 1 wherein said first shape disk includes a plurality of studs that extend toward the second side member and that are aligned with, and extend into, a plurality of bores that extend at least partially through the first hub to thereby releasably engage the first shape disk to said first hub.
 5. The yo-yo of claim 1 wherein said first hub includes a center-located nipple portion that extends through a complementary center-located thru-hole in the first shape disk.
 6. The yo-yo of claim 5 wherein an end portion of said nipple portion includes exterior threads engageable with interior threads located in a bore of the first fastener member.
 7. The yo-yo of claim 1 wherein the first side member further comprises a lock disk located in between the first fastener member and the first shape disk.
 8. The yo-yo of claim 7 wherein the first hub includes a plurality of studs that extend through apertures in the first shape disk and are received within bores in the first lock disk.
 9. The yo-yo of claim 1 wherein said fastener members are adapted to enable them to be easily grasped and rotated by hand.
 10. The yo-yo of claim 1 wherein the first fastener member interacts with an adjacent portion of the first side member to create a locking engagement of said fastener member.
 11. The yo-yo of claim 10 wherein when said first fastener member is rotated, an audible click will occur to signal a point in said rotation at which a locking engagement of the first fastener member is occurring.
 12. The yo-yo of claim 1 wherein said first fastener member is located adjacent a portion of the first side member that has an outwardly-facing surface that includes at least one indentation and wherein an inwardly-facing surface of the first fastener member includes at least one protuberance and wherein rotation of said fastener member can cause said at least one protuberance to be received in said at least one indentation to thereby create a locking engagement of said first fastener member with said adjacent portion of the first side member.
 13. The yo-yo of claim 1 wherein both of the first and second shape disks include a rim portion made of a non-rigid rubber material.
 14. The yo-yo of claim 1 wherein both of said first and second shape disks have a substantially planar configuration.
 15. The yo-yo of claim 1 wherein both of said first and second shape disks have a rim portion that is angled away from the tether to thereby provide the yo-yo with a butterfly shape.
 16. The yo-yo of claim 1 wherein each of said first and second hubs includes a cavity that contains a bushing made of a deformable material, wherein each bushing contacts, and is deformed by, a threaded portion of an axle pin of the axle structure, wherein a width dimension of a space located between the first and second side members can be adjusted by rotating one of said side members relative to the other of said side members, and wherein deformation of said bushings acts to bias said side members against rotation relative to said axle pin.
 17. A yo-yo comprising: first and second side members secured together in a spaced-apart relation by an axle structure; first and second hubs, wherein said first hub forms a portion of said first side member and has a tether-facing surface; first and second shape disks, wherein said first shape disk forms a portion of said first side member and said second shape disk forms a portion of said second side member, and wherein each of said shape disks has a rim portion; wherein said first hub includes a plurality of outwardly extending studs and said first shape disk includes a plurality of apertures complementary to said studs, and wherein said studs extend through said apertures to thereby non-rotatably engage said first shape disk to said first hub; first and second fastener members, wherein said first fastener member forms a portion of said first side member and is releasably secured to a portion of said first hub that extends through a center-located aperture in the first shape disk, and wherein said first fastener member functions to secure said first shape disk to said first hub; and wherein when said first shape disk is secured to said first hub, said first shape disk's rim portion will form at least a portion of an exterior rim surface of the first side member and thereby at least partially define the shape of the first side member whereby a user can change the shape of said first side member by removing the first shape disk and in its place installing a third shape disk wherein said third shape disk has a rim portion shaped differently than that of the first shape disk.
 18. A yo-yo comprising: first and second side members secured together in a spaced-apart relation by an axle structure; a tether secured to a portion of said axle structure; first and second hubs, wherein an inwardly-facing surface of said first hub includes a cavity into which is secured a nut that is threadedly engaged to exterior threads located on a first end portion of an axle pin of the axle structure, wherein said second hub has an inwardly-facing surface that includes a cavity into which is secured a nut that is threadedly engaged to exterior threads located on a second end portion of said axle pin, wherein said second hub forms a portion of said second side member, and wherein each of said hubs has a tether-facing surface; first and second shape disks, wherein said first shape disk forms a portion of said first side member and said second shape disk forms a portion of said second side member, wherein said first shape disk is releasably engaged to said first hub by an engagement apparatus that does not allow said first shape disk to rotate relative to said first hub, wherein said second shape disk is releasably engaged to said second hub by an engagement apparatus that does not allow said second shape disk to rotate relative to said second hub, and wherein each shape disk has a rim portion; first and second fastener members, wherein said first fastener member is releasably engaged to said first hub and functions to releasably secure said first shape disk to said first hub, wherein said second fastener member is releasably engaged to said second hub and functions to releasably secure said second shape disk to said second hub; and wherein each side member's shape disk includes a portion that at least partially forms the exterior surface of the side member's rim, and wherein a user can change the material of the rim portion of the yo-yo's side members by removing each side member's shape disk and installing in its place a replacement shape disk that has a rim portion made of a different material than the rim portion of the shape disk that was removed.
 19. A yo-yo comprising: first and second side members secured together in a spaced-apart relation by an axle structure, and wherein each of said side members is an assemblage of parts; a tether secured to a portion of said axle structure; first and second hubs, wherein said first hub forms a portion of said first side member and has a tether-facing surface; first and second shape disks, wherein said first shape disk forms a portion of said first side member and said second shape disk forms a portion of said second side member; first and second fastener members, wherein said first fastener member forms a portion of said first side member and is releasably secured to said first hub and located to capture the first shape disk between itself and said first hub, and wherein said first fastener member functions to secure said first shape disk to said first hub; wherein an outwardly-facing surface of each of said fastener members is adapted to enable the fastener members to be easily grasped and rotated by hand; and wherein a locking engagement employing at least one detent is used to releasably lock the first fastener member to an adjacent portion of the first side member.
 20. The yo-yo of claim 19 wherein when the first fastener member is rotated, the occurrence of the locking engagement will be signaled by an audible click.
 21. The yo-yo of claim 19 wherein an inwardly-facing surface of said first fastener member has a protuberance, a portion of said first side member located adjacent said first fastener member has at least one indentation complementary in shape and size to said protuberance, and wherein when said fastener member is applying an inwardly-directed pressure on said first shape disk and said first fastener member is rotated, said protuberance can slide into said indentation to cause an audible click. 